How can the security of a captcha system be improved to prevent automated attacks?

To improve the security of a captcha system and prevent automated attacks, one can implement additional layers of verification such as image distortion, audio challenges, or time-based puzzles. Additionally, regularly updating the captcha algorithm and using a combination of different captcha types can make it more difficult for bots to bypass the system. 

// Example of implementing image distortion in a captcha system
function generateCaptchaImage($text) {
    $image = imagecreatefromjpeg("captcha.jpg");
    $font = "arial.ttf";
    $color = imagecolorallocate($image, 255, 255, 255);
    $text = str_shuffle($text);
    imagettftext($image, 20, 0, 10, 30, $color, $font, $text);
    
    // Add image distortion here
    
    header('Content-type: image/jpeg');
    imagejpeg($image);
    imagedestroy($image);
}

$text = "CaptchaText123";
generateCaptchaImage($text);

Keywords

captcha system security automated attacks PHP functions libraries

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